Darley and Coolmore, respectively owned by Dubai’s ruler Sheikh Mohammed bin Rashid al-Maktoum and Irish billionaire John Magnier, opposed the Drayton South Mine because it would be too close to their stud farms, deemed to be "critical" to the nation's equine industry.

Anglo American had argued the Drayton South mine was an extension project essential to protect 500 jobs at its existing Drayton mine, which is due to end production in 2017.

The decision was qualified by the NSW Minerals Council as a "brutal double blow" for Anglo and the wider coal industry, which is struggling with a slump in prices, China’s recent imposition of tariffs on imports and increasing levels of environmental activism.

“It’s a black day for jobs in regional NSW. The NSW Government seems too busy patting itself on the back for the recent increase in housing activity in Sydney to notice the reality of economic life in regional NSW,” NSW Minerals Council CEO Stephen Galilee said in a statement.

Official figures show that more than 4,000 jobs have been lost at NSW mining operations over the last two years, with over 2500 coal jobs lost in the Hunter alone.